Process of coating metal foil with paraffin, and the product thereof



Patented Aug. 28; 1923.

UNITED STATES I 1,466,3s PATENT OFFICE.

HARRY NUSBAUM A.'ND JOSEPH NUSBAUM, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNORS TO I. E. 'SHARPLESS COMPANY, OF PHILADELPHIA, PENNSYLVANIA,

"A CORPORATION OF PENNSYLVANIA.

rnocnss or comma METAL rornwrrn rAnArriN, AND THE rnonucr 'rn'nnnon.

"No Drawing.

To allwhomitmay comm:

Be it known that 'we, HARRY NUsBAUM and J OSEPH NUSBAUM, citizens of the United States, residing at the city of Philadelphia,

'6 in the county of Philadelphia and State of Pennsylvania, have jointly invented a certain new and useful Improvement in Processes of Coating Metal Foil with Paraflin and the Product Thereof, of which the following is a specification.

Our invention relates primarily to a new method and means hereinafter described for fixedly applying a coating of paraffin, commonly called parafiin wax, to the surface of metal foils, such as tin foil or aluminum foil commonly employed, for sanitary and other reasons vhereinafter mentioned,

as a wrapper for those articles of food, such I for example as soft cheese, which require for commercial purposes, 'to be enclosed in a suitable wrapping material; but the ult1- mate object, of our invention is the new product resulting from the process, which is such a metal foil so coated and hence par- Mticularly well adapted as a Wrapper for such perishable articles, the composition,

coating being odorless and operating as a preservative of the wrapped contents from the destructive or deteriorating eifectiof air and moisture and other extraneous influences, and incidentally for sanitary reasons, and, because the composition produces a thin and transparent coating it can be advantageously used where the foil wrap- 5 per has previously had a label printed directly thereon. The novelty in the process and the resultant product, resides ,in the fact that the composition is of such character and has suchproperties, as hereinafter 49 stated, ;that it will attach itself, withtenaciously clinging 'eflect, to the surface of the. metal foil. l We are aware it was long well known in the art to coat the surface of paper, cloth and the like, with amelted composition of such paraflin wax, or with beeswax as a substitute, and sometimes with the addition to either or both, of resin, but in such disproportionate quantity as to make it objec- 50 tionable for several reasons. However the applicationof a paraffin coating to metal foil presented a very different problem from that of its application to paper or the like; and in a Patent No. 1399270 granted to one Application fiIed' March 31, 1921. Serial No. 548,537;

parts of the latter, the purified resin and pure beeswax, will apparently combine with the paraflin wax and cause it to attach itself fixedly to the skin surface of the foil to the extent at least, of not peeling or cracking under flexure from 'ordinary handling, and moveover produces a thin} odorless, colorless and hence transparent coating thereon. -While this composition fully performed the functions for which it was used, we found in 'it some'lack of pliability or excess of brittleness and some tendency to undue adhesiveness tending to tear the foil in handling it, which seemed to indicate the necessity for a solvent of the resin, as a constituent in the com osition,

and suggested to us to try aminera oil for this purpose, not inconsistent with the parafiin as a petroleum product, because we had learned, from a previous Patent No. 1194340 for a different composition and purpose, that such had' been used as a solvent of vegetable wax and gum; and also that it might otherwise operate beneficially on the other elements of our patented composition and produce the improved results we sought for and our experiments immediately made therewith orrthose then made under our direction, demonstrated satisfactorily to usthat the use of such a mineral oil in our composition, as such solvent and combining agent was desirable and very effective tov overcome both the objections stated.

Our present invention is predicated on that theory and is an improvement on our composition of that patent, or rather a sub stitute therefor, in .which,- while-the relative proportion of the base'paratfin waxremains the same, the relative percentage of beeswax and resin. are reduced, and a min- ,eral oil solvent, which, like the paraffiruis ion a derivative of petroleum, substituted to the extent to which the resin and beeswax are reduced. To these ends the novelty of our present process and product, consists'primarily in the discovery that a paraffin wax coating can be caused to fixedly adhere to the skin sur:

1ess translucent,

slightly greasy to the touch. It is a wellface of metal foil by admixing with it, in the melting pot, certain combining elements of the character hereinabove mentioned and substantially in the proportions hereinafter stated; and secondly in increasing the fluidity of the composition by raising its temperature some ten or twenty degrees C. above the melting point of its least melt-able constituent and so maintaining it during the application of the composition to the surface of the foil. 5

In the practice of our'invention we use commercial tin foil or aluminum foil, of a suitable thickness for the purpose for which it is to be ultimately used; and then make up a coating composition therefor consisting of the following elements, in substantially the relative proportions, stated in percentages of weight, as follows: Parafiin wax, 87.5 per cent; pure beeswax 5 per cent; purified resin 4 per cent, and mineral oil derived from petroleum 3.5 per cent.

The ingredients named in the relative proportions stated are mixed in a steam-jacketed kettle, preferably, in which they com-Y bine in a melted mass at about-100 C. to form a homogeneousmixture and of free fluidity; the mineral oil being preferably added in very small divided quantities at in tervals during the time required for themelting of the other elements. A slight increase of temperature, say 10 to 20 degrees F. above that stated for melting, will increase the fluidity and its heat, and is for those reasons desirable when applying the composition as a coating on metal foil.

Our new composition has, as its base, a pure paraflin sometimes called p-araflrin wax, which is a colorless or white solid, more or oderless, tasteless, and

known. commercial product, and is said to be a purified mixture of solid hydrocarbons commonly obtained from petroleum. That which we use and buy in the open market, has a melting point of about 5 C. It should form 85% to 87% by weight, of the total 'weight of our new composition.

The beeswax used in this composition should, to obtain the best results in all the respects stated, be entirely free from impurities, in other words the pure beeswax unadulterated, which is of a. light lemon color and has a melting point of about 65 C. or 150 F.,or very nearly the same as pure paraffin wax. It has the property of readily uniting with parafiin wax and purified resin.

out in the melting process. A very pure resin, of a character particularly compatible with the mineral oil, and which we have used with good results, is a product of the BarrettUheinical (30., readily obtained in the open market, and is commercially sold under the trade name Cumar which, perhaps,' is an abbreviated derivation of its technical descriptive name Paracoumarone. It is of the usual resin color, one grade of which is light brown, in color, whichsoftens at'about C. and melts at 90100 C. y

We combine with these-elements, preferably after bringing them into a melted and mixed state, (the resin constituent being the least meltable of them,) a small percentage of mineral oil, which, like the pan affin base, is also a derivative of petroleum, and is equally colorless, transparent, odorless and tasteless. A suitable example of it which wehave used with the best results,

, is that made and sold commercially by the Standard Oil Co. of New J ersey,under the trade name Acto. The miner-a1 oil is employed as a solvent of the resin and also for its probable toughening effect on the beeswax; and it apparently operates also to unite with them and the paraflin base in producinga homogeneous mixture. As the result of our repeated experiments and commercial use of it, we found that it entirely overcame the objectionable tendencies of the resin constituent in our previous composition, and produced a composition which gives a thin, transparent, and extremely pliable coating; these result-ant effects being markedly apparent.

The new composition is in liquid form, of

a dark brown, at the melting temperature When raised in temperature to say 120 C. to increase its fluidity and impart a' high temperature to it, a very thin and evenly distributed coating can behad by a quick dipping, by suitable mcaps, of the foil wrapper to be coated; a thin coating being less brittle and more pliable, and moreover more transparent, hence if applied to a metal foilhaving printing on it, will permit the printing thereon to be easily read through it. It sets or dries very romptly; will resist peeling or cracking wlien flexed under ordinary conditions of usage; is free from any odor, and, to the extent towhich the coated wrapping is so applied as to exclude air from its contents, will, for that reason, prevent the growth of aerobic molds on any food product thus brought into enclosing contact with it.

Having thus described our invention, we claim: a

1. The process of causing a'coating of' paraffin wax to fixedly adhere to the surface of metal foil, such as tin foil or aluminum paraffin wax, a mineral oil derived foil, which consists in combining with the paraffin wax, in a suitable vessel, under applied heat, purified resin, beeswax and a mineral oil derived from petroleum, in substantially the proportions specified, and maintaining the melting temperature and fluidity of the composition during the application thereof to the foil to be coated.

2. The process of producin and causing to fixedly adhere to the sur ace of metal foil an odorless, transparent, and moisture and air-resisting coating, which consists in forming a compound in a suitable Vessel, under applied melting heat, consistin of rom petroleum, purified resin, and natural beeswax, in substantially the proportions specified; then raising the temperature about 10 'to C. to increase the fluidity of the composition, and dipping therein the foil to be coated.

3. The new. product described which is a metal foil coated with a composition consisting of paraflin wax, beeswax, purified resin, and a mineral oil, in substantially the proportions specified, and capable of flexure without substantially disturbing the fixed adherence of the coating to the foil.

4. The new product describedwhich is a metal foil, such as .tin or aluminum foil having on its surface an odorless, thin an ing formed by the application thereto, in-a fluid and heated state, of a composition of paraffin. wax, beeswax, purified resin and mineral oil,'in substantially the proportions specified.

In testimony whereof, we have hereunto affixed our slgnatures this 28th day of March 1922.

HARRY NUSBAUM. JOSEPH NUSBAUM.

Witnesses: I

I. M. TUNIS, HARRY A. GREAR. 

